Silencer

ABSTRACT

A device for reducing noise produced by a relatively low-powered high speed combustion engine is adapted to be attached to the tailpipe. The device has a series of inter-connected spherical spaces in horizontal spaced alignment with a hollow sphere mounted concentrically in each space. The device is preferably manufactured in two complementary halves which are then attached to each other to complete the device.

United States Patent [151 3,704,763 Becker et al. [4 1 Dec. 5, 1972 s41 SILENCER 2,051,675 8/1936 Blanchard ..181/47 B 72 Inventors: Richard B. Becker, 34 ocean 2,928,491 3/1960 Crouch ..181/47 B View Ave., Whittier, Calif. 90605; Clarence C. Chapman, 7860 FOREIGN PATENTS 0R APPLICATIONS Raviller Dr., Downey, Calif. 90240 992,706 7/1951 France ..181/47 B v [22] Filed: Feb. 9, 1972 1,292,669 4/1969 Germany ..181/47 B [21] Appl. N0.: 224,857 Primary Examiner-Robert S. Ward, Jr.

I Attorney-Vernon D. Beehler et a1.

[52] US. Cl. ..181/47 B,181/53, 181/57,

1 1/72 [57] ABSTRACT [51] Int. Cl ..F0ln 1/08, FOln 7/02, FOln 7/20 A d i f reducing noise produced by a relatively [58] new of search-M18155 47 47 low-powered high speed combustion engine is adapted 181/53 35 72 to be attached to the tailpipe. The device has a series of inter-connected spherical spaces in horizontal [561' References Cited spaced alignment with a hollow sphere mounted con- UNITED STATES PATENTS centrically in each space. The device is preferably manufactured in two complementary halves which are 787,860 4/1905 Sharpe ..181/53 then attached to each other to complete h i 1,071,528 8/1913 Rapp ....181/49 1,816,245 7/1931 W'olford ..181/70 9 Claims, 4 Drawing Figures SILENCER In the operation of relatively. low-powered high speed engines whether of the two-cycle or four-cycle type, there is an accompanying staccato exhaust noise which persists. despite employment of conventional mufflers. One of the difficulties confronting the design of an effective silencer for exhaust noises of the type described is the fact that back pressure must be heldto a minimum because of the low-power operation if such engines are to perform effectively. Silencing, of course, is possible by means already known but such means, for the reasons mentioned, cannot be employed successfully for such small capacity low-power engines which, for example, to drive vehicles such as motor scooters and low-powered cars have to operate at speeds well above average. I

It is thereforeamong the objects of the invention to provide a new and improved silencer capable of being effectively used on a low-powered high speed combustion engineand wherein relatively little back pressure is generated.

Anotherv object of the invention is to provide a new and improved silencer capable of being effectively used on a low-power high speed combustion engine which is of such design and construction that the silencer can be matched to the needof some particular engine.

Still another object of the invention is to provide a new and improved silencer for a combustion engine adapted to be attached to a conventional muffler outlet wherein the passages through the silencer are such that the objectionable staccato burst is effectively silenced without sacrifice of engine efficiency.

Still another object of the invention is to provide a new and improved silencer for a combustion engine which is of relatively simple construction such that it can be readily and inexpensively made to perform with good efficiency, the structure being such that it can be fabricated at a moderate price.

With these and other objects in view, the invention consists in the construction, arrangement, and combination of the various parts of the device, whereby the objects contemplated are attained, as hereinafter set forth, pointed out in the appended claims and illustrated in the accompanying drawings.

FIG. 1 is a side perspective -view of the silencer shown in the position it would have attached to a conventional muffler outlet.

FIG. 2 is a longitudinal sectional view taken on the line 2 2 of FIG. 1.

FIG. 3 is a cross sectional view taken on the line 3 3 of FIG. 2.

FIG. 4 is a longitudinal sectional view of a second form of the invention.

In an embodiment of the invention chosen for the purpose of illustration, there is shown a silencer indicated generally by the reference character shown attached to an exhaust outlet 11 of a substantially conventional type muffler 12. The silencer is embodied in a jacket 13 which, in the chosen embodiment, incorporates four longitudinally aligned substantially round spherical housings 14, 15, 16, and 17. These housings contain respective round-walled chambers 18, 19, 20, and 21. The walls of the housings are relatively thin and may be constructed of sheet metal or other appropriate material capable of withstanding customary exhaust temperatures without deteriorating.

A tubular member 22 provides an inlet passage 23 to admit the customary exhaust gases coming from one of the engines of the type made reference to, the passage also being the means by which noise generated in the engine finds its escape. I

Between the housing 14 and is a relatively shorter tubular member 24 providing a passage 25 from the chamber 18 to the chamber 19. Similarly, a tubular member 26 interconnects chambers 19 and 20 and a tubular member 27 interconnects chambers 20 and 21, the tubular member 26 providing a passage 28 and a tubular member 27 providing a passage 29. An outlet orifice 30 from the chamber 21 at the extreme downstream position is made use of without a surrounding tubular member.

In the chamber 18 is an obstruction which takes the form of a hollow sphere 35. The sphere is mounted concentrically with respect to the rounded walls of the chamber 18, the hollow sphere being supported by means of braces 36 and 37 which are diametrically opposite to each other, the braces being received in respective recesses 38 and 39 in the wall of the jacket 13. A hollow space 40 within the sphere 35 is without access from the exterior.

Similarly, a hollow sphere 41 is concentrically mounted within the chamber 19 by means of braces 42 and 43. Likewise a hollow sphere 44 is concentrically mounted within the chamber 20 by use of braces 45 and 46. The endmost chamber 21 has a hollow sphere 47 concentrically mounted within it by means of braces 48 and 49. A screen 50 is provided in a position extending over the outlet orifice 30 to prevent occasional sparks from being expelled with the exhaust gasses.

The rounded form of the respective housings and hollow spheres in the chosen embodiment may be effectively described as oblate spheroids. It will be appreciated, however, that essentially rounded forms which may fall short of the oblate spheroidal forms made reference to in precise concentric disposition may also be employed.

In order to be able to construct a device such as that hereinbefore described, it has been found useful to build the jacket 13 in two complementary halves as suggested by the line of division of FIG. 3. By resorting to the suggested means of construction, the spacing of the hollow spheres within the respective chambers can be readily accomplished while the work is done at the open sides of the respective halves of the final device which thereafter can be matched face-to-face and the butting edges sealed in a conventional fashion.

By having the outside diameter of the spheres at least as great and preferably greater than the inside diameter of the interconnecting passages 23, 25, 28, and 29. exhaust gases and the noise stream as it enters the passage 23 is diverted around the spherical exterior of eachhollow sphere in turn and, being so diverted, is also forced to follow a curved path defined by the walls of the respective chambers 18, 19, 20, and 21.

Pressure differentials caused by the passage of air at the usual speeds over spherical exterior surfaces create an effective turbulence which is highly instrumental in killing the staccato sound which accompanies the stream of exhaust air through the silencer. I

In the form of invention of FIG. 4 there are employed three concentric substantially spherical housings 60, 61, and 62 which, in the chosen embodiment, are substantially equally spaced one from another. The housings form respective chambers 63, 64, and 65. Within the innermost chamber 63 and concentric with respect to the chamber 60 is an imperforate spherical obstacle 66. Posts 67, 68, and 69 are employed to secure the housings and the spherical obstacle in their respective positions.

A tubular element 70 forms an open upstream end 71 which is adapted to be connected to the exhaust outlet ll previouslymade reference to. The tubular element extends through an opening 72 in the housing 62 and through an opening 73 in the housing 71 and finally through an opening 64 in the chamber 60 thereby providing a passageway 75 into the innermost chamber On the opposite side of the innermost chamber 63 is an outlet opening 76 which forms a passageway between 'the intermost chamber 63 and the intermediate chamber 64 through which exhaust gases pass whereby to then travel in a reverse direction through the intermediate chamber 64 to an outlet opening 77 through which the gases enter the outermost chamber 65, again experiencing a reversal of flow. A fillet 78 between the housing 62 and the tubular element 70 serves to modify and smooth out the transition in the direction of air flow from the intermediate chamber 64 to the outermost chamber 65. On the side of the outermost housing 62 opposite from the location of the tubular element 70 there is an outlet opening 79 from which the exhaust gases emerge and are discharged through a screen 80 to the atmosphere.

As will be noted from an examination of the various passages in the form of device of FIG. 4 there are two reversals of flow for the exhaust gases and these reversals of flow are accompanied by a progressively expanding space which accepts the gases due to the fact that the sizes of the housing and corresponding chambers areprogressively larger. Moreover air being discharged from any one of the chambers approaches the outlet opening of that particular chamber from all sides at once and then travels through the outlet which is of somewhat restricted character and furthermore under circumstances where air from one side of the outlet opening tends to travel cross-current with respect to air approaching from the opposite side as suggested by the arrows in FIG. 4, which aids in dispersing and silencing the sound.

While the invention has herein been shown and described in what is conceived to be a practical and effective embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices.

Having described the invention, what is claimed as new in support of Letter Patent is:

1. A silencer for a combustion engine comprising a hollow jacket having opposite open upstream and downstream ends and a plurality of substantially round walled chambers spaced from each other with connecting passages therebetween, and a substantially roundshaped obstruction mounted therein and spaced from the wall of the respective chamber.

2. A silencer as in claim 1 wherein the chambers are longitudinally aligned and there is a round-shaped obstr ction in each c amber.

3 A silencer as i 11 claim 2 wherein the chambers and obstructions are in the shape of oblate spheriods and the obstructions are concentrically mounted in the respective chambers.

4. A silencer as in claim 2 wherein the obstructions are hollow and of relatively thin material.

5. A silencer as in claim 2 wherein there are tubular walled passages interconnecting said chambers.

6. A silencer as in claim 2 wherein there are not less than four chambers with an obstruction mounted in each chamber.

7. A silencer as in claim 1 wherein the chambers are concentric and of various sizes which are progressively larger from the innermost chamber to the outermost chamber and wherein there are outlet openings alternating in opposite directions.

8. A silencer as in claim 7 wherein the round shaped obstruction is within the innermost chamber.

9. A silencer as in claim 7.wherein there is an inlet passageway at the open upstream end which extends through the walls of the chambers to the innermost chamber and wherein the open downstream end is an opening in the outermost chamber. 

1. A silencer for a combustion engine comprising a hollow jacket having opposite open upstream and downstream ends and a plurality of substantially round walled chambers spaced from each other with connecting passages therebetween, and a substantially roundshaped obstruction mounted therein and spaced from the wall of the respective chamber.
 2. A silencer as in claim 1 wherein the chambers are longitudinally aligned and there is a round-shaped obstruction in each chamber.
 3. A silencer as in claim 2 wherein the chambers and obstructions are in the shape of oblate spheriods and the obstructions are concentrically mounted in the respective chambers.
 4. A silencer as in claim 2 wherein the obstructions are hollow and of relatively thin material.
 5. A silencer as in claim 2 wherein there are tubular walled passages interconnecting said chambers.
 6. A silencer as in claim 2 wherein there are not less than four chambers with an obstruction mounted in each chamber.
 7. A silencer as in claim 1 wherein the chambers are concentric and of various sizes which are progressively larger from the innermost chamber to the outermost chamber and wherein there are outlet openings alternating in opposite directions.
 8. A silencer as in claim 7 wherein the round shaped obstruction is within the innermost chamber.
 9. A silencer as in claim 7 wherein there is an inlet passageway at the open upstream end which extends through the walls of the chambers to the innermoSt chamber and wherein the open downstream end is an opening in the outermost chamber. 